Today there is work ongoing to provide different types of public warnings systems in order to, for example, introduce support for an Earthquake Tsunami Warning System (ETWS), enabling transmission of warning notifications about coming earthquakes and/or tsunamis through mobile stations. The ETWS warning notifications are divided into two types, a primary notification and a secondary notification.
The primary notification is sent in order to notify users about the most urgent event in seconds rather than minutes, such as imminent occurrence of an earthquake and/or the like. There are requirements to reach the users/mobile stations with an ETWS primary notification message within 4 seconds. In order to avoid that fake messages are received causing chaos, inclusion of authentication information in the primary notification will most likely be needed. An alternative to authenticate the information is to have authentication information in the form of a digital signature, e.g. 41 bytes of information if using Digital Signature Algorithm (DSA) signatures and/or the like.
The secondary notification is sent to give the users supplementary information that is of lesser urgency, such as instructions on what to do, where to get help, map to refuge facilities, time table of food distribution, and/or the like.
A Cell Broadcast Service (CBS) based solution has been envisaged for transmission of the ETWS warning notifications, wherein an ETWS message is broadcasted on control channel to all mobile stations within a cell.
Considering ETWS it has been decided that a PAGING message is available in order to satisfy the ‘within 4 seconds’-requirement.
The current assumption is to use the PAGING TYPE 1 message for the primary notification, reaching user equipments (UEs) in idle mode and in connected mode that listens to a paging channel. Using the paging channel is considered the main option in order to satisfy the requirement to reach the UEs within 4 seconds. However, there is a desire to reach as many UEs as possible within the time limit with a reliable emergency notification.